1. Field of the Invention
The invention relates to the field of flexible media handling, and in particular, to reconfigurable media path elements for use in media handling systems.
2. Related Art
Conventional paper transport systems, such as incorporated into printers and copiers, are typically custom-designed units. Each unit includes a heavy frame that defines one or more paper paths, and sets of pinch rollers that move sheets of paper through the paper paths. However, because prior art transport systems are custom designed to meet the differing needs of specific printing systems, field reconfigurability and programmable reconfigurability are generally not readily achievable.
Furthermore, to enhance paper-handling capabilities, it is desirable for a paper transport system to have redirecting capabilities that allow the paper transport system to transport different sheets of paper along different paper paths. Conventional paper transport systems typically use movable gates to provide this redirection capability.
For example, U.S. Pat. No. 5,303,017, issued Apr. 12, 1994 to Smith, describes a gate-based redirection mechanism, as shown in FIGS. 1A and 1B. In FIGS. 1A and 1B, two horizontal baffles 111 and 112 define a first paper path 114, while a sheet diversion chute 113 defines a second paper path 115. Pinch rollers 121, 122, and 123 can then move sheets of paper through paper paths 114 and 115, based on the orientation of a diverter gate 130.
In FIG. 1A, diverter gate 130 is in a horizontal position, thereby allowing pinch rollers 121 and 122 to pass a sheet of paper through first paper path 114 in a transport direction 101. In FIG. 1B, diverter gate is rotated downwards (in a diagonal orientation), thereby blocking paper path 114 and allowing pinch rollers 122 and 123 to pass a sheet of paper through second paper path 115 in a transport direction 102.
In this manner, diverter gate 130 controls the paper transport direction in FIGS. 1A and 1B. However, as the speed and routing requirements placed on paper transport systems increase, elements such as diverter gate 130 can limit paper transport capabilities.
Specifically, the “joint” of diverter gate 130 (i.e., the region where diverter gate 130 makes a movable interface with the frame (baffle 111)) creates a surface discontinuity in the paper path. This discontinuity limits the reliability and performance of the transport system by creating a location at which the edges of paper sheets can catch or stub, particularly if the sheets are curled or have flaws such as “dog ears”. This stubbing problem is exacerbated as the speed of the paper transport is increased.
Note that while diverter gate 130 can sometimes be shaped to reduce the effects of the surface discontinuity in one direction, the joint will typically not be suitable for paper transport in the reverse direction. For example, in FIG. 1A, the tapered profile of diverter gate 130 presents a relatively non-stubbing paper path 114 in transport direction 101, attempting to move paper in the opposite direction would result in stubbing at joint A.
Accordingly, it is desirable to provide a system and method for creating highly configurable and high-performance paper transport systems which eliminate the causes of stubbing and jams.